Raspberry and vanilla vacherin

1.Bring cream, milk, vanilla bean and seeds to the simmer over medium-high heat. Meanwhile, whisk yolks and sugar in a bowl until thick and pale. Pour cream mixture over, whisk to combine, then return to pan and stir continuously until mixture thickly coats a spoon (5-6 minutes). Transfer to a bowl, refrigerate until chilled, then churn in an ice-cream machine, transfer to a container and freeze until required.

2.Meanwhile, for raspberry sorbet, stir sugar, glucose and 60ml water in a small saucepan over medium-high heat until sugar dissolves. Bring to the boil, cook for 30 seconds, then set aside to cool. Process raspberries, lemon juice and sugar syrup in a food processor to a smooth purée, then pass through a fine sieve (discard seeds). Churn in an ice-cream machine, then freeze until required.

3.For meringue, preheat oven to 120C. Whisk eggwhite and a pinch of salt in an electric mixer until soft peaks form, then, while whisking continuously, gradually add caster sugar. Whisk until glossy, then whisk in vanilla paste. Sieve icing sugar and cornflour over and fold to combine. Draw two 10cm x 21cm rectangles on each of 2 pieces of baking paper (for 4 rectangles in total) and place, pencil-side down, onto lightly oiled oven trays. Using the templates as a guide, spread meringue into 1cm-thick rectangles, smooth tops and bake, swapping trays halfway through cooking, until crisp but not coloured (1-1½ hours). Cool completely on trays. Meringue will keep stored in an airtight container for a week.

4.Remove ice-cream and sorbet from freezer to soften slightly. Meanwhile, line a 10cm x 21cm loaf tin with baking paper and place a meringue rectangle in the base (trim edges if necessary). Spread vanilla ice-cream over to 1cm thick, smooth top, then gently press another meringue rectangle on top. Spread raspberry sorbet to 1cm thick over (there may be some sorbet left over), smooth top, then gently press another meringue rectangle on top. Repeat with another layer of vanilla ice-cream and finish with the remaining meringue rectangle. Cover and freeze overnight.

5.To serve, dip loaf tin in hot water and unmould vacherin onto a board. Thickly slice with a hot, wet knife, transfer to chilled serving plates, scatter with fresh raspberries and serve immediately.